]{UJ>S AXI) LEAVES. 39 



upon the potiole raid midrib. They yield fluids that arc 

 oily, saccharine, and acid, as their peculiar secretions may 

 develop. In the orange and lemon these glands are im- 

 bedded in the lamina, presenting the appearance of small 

 yellow grains : if they are pricked with a needle, the oil 

 will be seen with the naked eye rising from the orifice. 



82. Other leaves are covered with a coating varying in 

 softness from the velvet down of the mouse-ear, through 

 all the gradations of woolly mullein, to the sharp prickles 

 of the thistle. They are described under the various names 

 of hairy, villous (Ld^tin, vilhis, haivy), pubescent (which also 

 means hairy), ciliate (Latin, cilia), muricate (Latin, mnrcx, 

 sharp-pointed), etc. ; all of which, being new Avords to you, 

 must be found in the Glossary and committed to memory. 



83. Our lesson upon leaves is now closed, and I hope 

 you Avill remember all that has been said concerning this 

 organ, so necessary to the beauty, growth, and life of the 

 tree. Did you ever think how this world would look if all 

 the leaves were gone ? You have seen them fade and fall 

 in autumn, but it was when the chill air drove you within 

 doors, when birds, flowers, and leaves were all gone ; and, 

 besides, you knew they would all come again. But think 

 of the blazing sun of the long summer days shining on 

 barren hills and scorched plains, without a green leaf any- 

 where ! They seem very insignificant and unimportant, 

 but summer would not be summer without them. And, 

 moreover, if they were all destroyed, the whole earth would 

 perish for lack of their sustaining care; for they not only 

 feed the tree and plant, but no animal life could exist with- 

 out them. The wdiole atmosphere would become so noxious 

 without their regulating power, that death to all animal 

 life would ensue. As the sun regulates the boundary 

 between day and night, so do these seemingly insignificant 



82. What of the down upon plants ? The difTercnt terms ? 



83. What would be the consequence of universal death to the leaves? "What 

 if leaves were to reverse their actions ? Can you hope to understand all this now ? 



